The issue of non-destructive testing ratio on pressure vessel design drawings
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The section on the design drawings regarding the proportion of non-destructive testing states: “A – Cylinder: RT 20% and >250 mm; B – Head: RT 100% (Grade II acceptable).” So, should the circumferential welds of both the head and the cylinder be subjected to 100% RT testing?
I guess it should be: Cylinder A, RT20% and >250mm
Reply to 1# 445295403: If the head is not a spherical head, the butt welding joint between the head and the cylinder can undergo non-destructive testing at a rate of 20% or more.
I would like to ask, what if the head is a spherical one?
Since its joint belongs to Category A, 100% non-destructive testing must be carried out.
It can be inferred from \"cylinder RT20% and >250mm\" that the Class A and B welds of this equipment are subject to partial radiographic inspection, with a grade of III as acceptable. And “head RT100% (Grade II qualified)” implies that the weld coefficient for the head is 1.0. Therefore, whether the head is a spherical head or not, the circumferential weld between the head and the cylinder should be subject to local radiographic testing and must meet Grade III requirements.
Reply to 1# 445295403: Of course it’s RT100%. The circumferential weld between the lower head and the cylinder is a Class B weld, and therefore it should be inspected using the Class B testing methods and at the required proportions.
I don’t understand the meaning of this selection; generally, the requirements for Class A welded joints are stricter than those for Class B welded joints. I seek advice from experts
The 100% RT mentioned here refers to the welds at the joint of the head; for the cylinder, it is 20% RT, and the welds between the cylinder and the head are also inspected at 20% RT. Agree with the opinion from floor 6.
The 100% RT mentioned here refers to the welds at the joint of the head; for the cylinder, it is 20% RT, and the welds between the cylinder and the head are also inspected at 20% RT. Agree with the opinion from floor 6.
The A and B mentioned by the poster don’t refer to type A and type B welds; they probably refer to sequence numbers, that is, the 1st cylinder, the 2nd head